BACKGROUND: With the introduction of nurse-initiated and -managed antiretroviral therapy (NIMART), new challenges have emerged with regard to the prescribing and dispensing of ART by nurses. One of the key challenges is ensuring adequate pharmaceutical services at PHC clinics. OBJECTIVE: The objective of the study was to evaluate the adequacy of pharmaceutical services for the provision of ART in PHC clinics. METHOD: A quantitative descriptive study was undertaken in 20 (43%) randomly selected, eligible clinics in the uMgungundlovu district of KwaZulu-Natal, South Africa. RESULTS: Clinics used allocated medicine rooms for storing medication, as there were no pharmacies. Problems identified were: insufficient storage space (50%; n = 10); inadequate security (40%; n = 8); poor air conditioning (20%; n = 4), and functional stock-outs of essential drugs (80%; n = 16). Professional nurses performed the tasks of managing drug supply and prescribing and dispensing medication as there were no pharmacists or pharmacist's assistants in these clinics. CONCLUSION: Human resource constraints necessitate professional nurses to manage drug supplies and to prescribe and dispense medication in resource-constrained PHC clinics. Clear guidelines tailored for PHC are needed to assist nurses in maintaining pharmaceutical service standards when ART services are decentralised.